Section 3 The Hydrosphere and Biosphere

Objectives

Name the three major processes in the water cycle.

Describe the properties of ocean water.

Describe the two types of ocean currents.

Explain how the ocean regulates Earth’s temperature.

Discuss the factors that confine life to the biosphere.

Explain the difference between open and closed systems.

Chapter 3

The Hydrosphere

The hydrosphere includes all of the water on or near the Earth’s surface.

This includes water in the oceans, lakes, rivers, wetlands, polar ice caps, soil, rock layers beneath Earth’s surface, and clouds.

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The Water Cycle

The water cycle is the continuous movement of water from the ocean to the atmosphere to the land and back to the ocean.

Evaporation is the change of a substance from a liquid to a gas.

Water continually evaporates from the Earth’s oceans, lakes, streams, and soil, but the majority evaporates from the oceans.

Chapter 3 Section 3 The Hydrosphere and Biosphere

The Water Cycle

Condensation is the change of state from a gas to a liquid.

Water vapor forms water droplets on dust particles which then form clouds in which the droplets collide to create larger, heavier drops that then fall from the clouds as rain.

Precipitation is any form of water that falls to the Earth’s surface from the clouds, and includes rain, snow, sleet, and hail.

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The Water CycleChapter 3 Section 3 The Hydrosphere and

Biosphere

Earth’s Oceans

All of the oceans are joined in a single large interconnected body of water called the world ocean. The world ocean play important roles in the regulation of the planet’s environment.

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Earth’s Ocean

The largest ocean on Earth is the Pacific Ocean with a surface area of about 165,640,000 km2.

The deepest point on the ocean floor, the Challenger Deep, is found in the Pacific Ocean.

The Challenger Deep is located east of the Philippine islands and the bottom of the Mariana Trench and is 11,033m below sea level which is deeper than Mount Everest is tall.

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Earth’s Oceans

Oceanographers often divide the Pacific Ocean into the North Pacific and South Pacific based on the direction of the surface current flow in each half of the Pacific Ocean.

Surface currents in the Pacific move in a clockwise direction north of the equator.

Surface currents in the Pacific move in a counter-clockwise direction south of the equator.

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Earth’s Oceans

The second largest ocean on Earth is the Atlantic Ocean, and covers about half the area of the Pacific Ocean which is a surface area of about 81,630,000 km2.

Like the Pacific Ocean, the Atlantic Ocean can be divided into a north and south half based on the directions of surface current flow north and south of the equator.

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Earth’s Oceans

The Indian Ocean is the third largest ocean on Earth with a surface area of 73,420,000 km2.

The smallest ocean is the Artic ocean which covers 14,350,000 km2.

The Artic Ocean is unique because much of its surface is covered by floating ice, called pack ice, which forms when either waves or wind drive together frozen seawater, known as sea ice, into a large mass.

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Ocean Water

The difference between ocean water and fresh water is that ocean water contains more salts.

Salinity is a measure of the amount of dissolved salts in a given amount of liquid.

Salinity is lower in places that get a lot of rain or in places where fresh water flows in to the sea. In contrast, salinity is higher where water evaporates rapidly and leaves the salts behind.

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Ocean Water

Most of the salt in the ocean is sodium chloride, which is made up of the elements sodium and chloride, although many other elements can be found in the ocean as well.

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Temperature Zones

The surface of the ocean is warmed by the sun, while the depths of the ocean, where sunlight never reaches, are very cold, just above freezing.

Surface waters are stirred up by waves and currents so the warm surface zone may be as much as 350 m deep.

Below the surface zone is the thermocline, which is layer about 300 to 700 m deep where the temperature falls rapidly.

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Temperature ZonesChapter 3 Section 3 The Hydrosphere and

Biosphere